Journal Published Online: 06 October 2017
Volume 40, Issue 6

A Method for Directly Measuring the Hydraulic Conductivity of Unsaturated Soil

CODEN: GTJODJ

Abstract

Numerous methods, such as the Gardner outflow analysis method and the van Genuchten-Mualem prediction model, have been developed to estimate the hydraulic conductivity of unsaturated soil in multistep outflow experiments. In the Gardner outflow analysis method, the hydraulic conductivity is estimated based on the diffusivity calculated from the line fitted to the water outflow. In contrast, in the van Genuchten-Mualem prediction model, it is predicted via the curve-fitting parameters based on the measured soil water retention curve (SWRC). However, a major drawback of these two approaches is that variation of hydraulic conductivity during each step of the outflow process cannot be represented. In this paper, an improved pressure plate instrument with an evaporation compensation system is developed to measure the transient water content curve (TWCC) of the soil in multi-step outflow experiments. The SWRCs of silicon micro-powder (SMP) and Guangxi Guiping clay (GGC) are derived from this transient curve. Therefore, a direct measurement method is presented to describe the change of hydraulic conductivity during each step. Comparison with the Gardner outflow analysis method and the van Genuchten-Mualem prediction model indicates that our approach shows better agreement with test data for these two types of soils.

Author Information

Shao, Longtan
State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, Liaoning, China Department of Engineering Mechanics, Dalian University of Technology, Dalian, Liaoning, China
Wen, Tiande
State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, Liaoning, China Department of Engineering Mechanics, Dalian University of Technology, Dalian, Liaoning, China
Guo, Xiaoxia
State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, Liaoning, China Department of Engineering Mechanics, Dalian University of Technology, Dalian, Liaoning, China
Sun, Xiang
State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, Liaoning, China Department of Engineering Mechanics, Dalian University of Technology, Dalian, Liaoning, China
Pages: 10
Price: $25.00
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Stock #: GTJ20160197
ISSN: 0149-6115
DOI: 10.1520/GTJ20160197